474 BULLETIN 179, UNITED STATES NATIONAL MUSEUM 



closed nest and found within the dead body of a Swallow. This bird had 

 probably died a natural death, and the friends being unable to remove the 

 body, and knowing it would soon become offensive, adopted this method of 

 sealing it up. 



Occasionally three swallows may be seen engaged in building one 

 nest. E. O. Grant (Forbush, 1929) watched a nest at Long Lake, 

 Allegash, Maine, that was built by three birds, and he says that they 

 all took turns in incubating the eggs. He believed them to be two 

 males and a female. Brewster (1906) in his study of cliff swallows in 

 the Cambridge region of Massachusetts found as a rule two birds in 

 each nest, but several of the nests he examined sheltered three birds 

 each. Brewster concludes that there is good reason to suspect that 

 cliff swallows sometimes practice polygamy or polyandry. 



The time required to build a nest varies a great deal with different 

 pairs of birds, at least as reported by various observers. Knight 

 (1901) states that 10 to 14 days are required to finish the nest. In 

 my own experience in watching the building of a nest in a colony 

 at Kent Island, Bay of Fundy, 5 days elapsed from the time the 

 first pellets of mud were applied to the time the nest was ready for 

 its lining. Three days later the first egg was laid. Ordinarily it 

 requires a week for nest construction but the weather conditions, 

 mud supply, and amount of disturbance are factors that will mate- 

 rially affect the length of time. 



Most all observers agree that cliff swallows in general raise two 

 broods of young during any one breeding season. Hatch states that 

 even three broods are sometimes reared, but I am inclined to believe 

 that is very exceptional. 



The incubation period varies from 12 to 14 days according to vari- 

 ous authorities. The time that elapsed from the date of the laying 

 of the last egg to the hatching of the first young in a nest which I 

 observed at Kent Island was 13 days. 



Eggs. — [Author's note: The number of eggs in a complete set 

 varies from three to six, but four or five eggs constitute the usual 

 complement. They vary in shape from ovate to elliptical-ovate, or 

 rarely to elongate-ovate. The ground color is .white, creamy white, 

 or pinkish white. Some eggs are evenly, either sparingly or thickly, 

 marked with fine dots or small spots, or a mixture of both ; and some 

 have a few small blotches. In some the markings are concentrated 

 at the larger end or coalesced elsewhere into a dense wreath. The 

 markings are in various shades of light and dark browns, or "brown- 

 ish drab," with underlying spots or small blotches in the paler shades 

 of "Quaker drab." Very rarely the eggs are entirely unmarked. The 

 measurements of 50 eggs average 20.3 by 13.9 millimeters; the eggs 

 showing the four extremes measure 22.9 by 14.2, 22.4 by 15.2, 17.3 by 

 13.2, and 18.8 by 12.7 millimeters.] 



